This invention relates to a container closure of the type in which at least one flap is integrally hinged to the top panel of the closure and is adapted to be swung upwardly and downwardly to open and close a dispensing opening which is formed through the top panel. More specifically, the invention relates to a closure of the type in which means hold the flap securely in its closed position until the container is first opened and, at the same time, provide a visual indication as to whether the container has been tampered with and opened prior to purchase by the consumer. Such a closure is commonly referred to as being a tamper-evident closure.
A closure of this general type is disclosed in Foster U.S. Pat. No. 4,621,744. In that closure, a tear-away strip extends along the front edge of the closure flap and is connected to such edge by frangible webs. The tear strip is anchored releasably to the top panel of the closure and normally holds the flap in its closed position to preserve the integrity of the seal and to provide a clear indication that the container is of the tamper-evident type. By pulling upwardly on one end of the strip, the latter may be torn away from the panel and the flap to permit opening of the flap. If the strip is partially torn or is absent, the consumer is warned that the original seal may not be intact.
While the tamper-evident feature of the closure of the aforementioned Foster patent is effective, it is somewhat complex in that pins which are molded integrally with the top panel project upwardly through openings formed through the strip. After the closure has been molded and the flap has first been closed, it is necessary to heat stake the upper ends of the pins to cause the pins to mushroom over and captivate the strip downwardly against the panel. Moreover, it is necessary to provide tear-away buttons in the openings in the strip in order to insure tearing away of the strip.